github.com/wasilibs/wazerox@v0.0.0-20240124024944-4923be63ab5f/internal/engine/wazevo/backend/isa/arm64/abi_entry_arm64.s (about)

     1  //go:build arm64
     2  
     3  #include "funcdata.h"
     4  #include "textflag.h"
     5  
     6  // See the comments on EmitGoEntryPreamble for what this function is supposed to do.
     7  TEXT ·entrypoint(SB), NOSPLIT|NOFRAME, $0-48
     8  	MOVD preambleExecutable+0(FP), R27
     9  	MOVD functionExectuable+8(FP), R24
    10  	MOVD executionContextPtr+16(FP), R0
    11  	MOVD moduleContextPtr+24(FP), R1
    12  	MOVD paramResultSlicePtr+32(FP), R19
    13  	MOVD goAllocatedStackSlicePtr+40(FP), R26
    14  	JMP  (R27)
    15  
    16  TEXT ·afterGoFunctionCallEntrypoint(SB), NOSPLIT|NOFRAME, $0-24
    17  	MOVD goCallReturnAddress+0(FP), R20
    18  	MOVD executionContextPtr+8(FP), R0
    19  	MOVD stackPointer+16(FP), R19
    20  
    21  	// Save the current FP(R29), SP and LR(R30) into the wazevo.executionContext (stored in R0).
    22  	MOVD R29, 16(R0) // Store FP(R29) into [RO, #ExecutionContextOffsets.OriginalFramePointer]
    23  	MOVD RSP, R27    // Move SP to R27 (temporary register) since SP cannot be stored directly in str instructions.
    24  	MOVD R27, 24(R0) // Store R27 into [RO, #ExecutionContextOffsets.OriginalFramePointer]
    25  	MOVD R30, 32(R0) // Store R30 into [R0, #ExecutionContextOffsets.GoReturnAddress]
    26  
    27  	// Load the new stack pointer (which sits somewhere in Go-allocated stack) into SP.
    28  	MOVD R19, RSP
    29  	JMP  (R20)